1. Field of the Invention
The present invention relates to an electromagnetic relay.
2. Description of the Related Art
As a device which is arranged in an electrical circuit to electrically connect and disconnect it, an electromagnetic relay is known. An electromagnetic relay is provided with an electromagnet, an armature which faces the electromagnet, and contacts which are connected to the armature. In the electromagnetic relay, when the coil is energized, the armature is pulled by the electromagnet causing the armature to move. Due to movement of the armature, the contacts are made to move and a plurality of contacts are electrically contacted or separated from.
Japanese Utility Model Publication No. 4-58933A discloses a polar relay which is provided with a moving member which includes a permanent magnet and can move when a coil is energized and a contact member which is formed so as to contact or separate from the moving member and which has a contact part which is inclined with respect to the axial direction.
Japanese Patent No. 2797261B2 discloses an electrical switching device which is provided with a moving contact plate and a fixed terminal plate, wherein the moving contact plate extends vertical to the up-down movement direction, that is, in a horizontal direction, and the fixed terminal plate descends somewhat to the outside in a direction of arrangement of a pair of moving contacts.
A general electromagnetic relay is structured by a base member which is formed by resin etc. to which a moving electrode plate and a fixed electrode plate are fixed. The moving electrode plate and fixed electrode plate are formed as elongated plate shapes and are arranged separated from each other. Operation of the armature is transmitted to the moving electrode plate, whereby the moving electrode plate deforms and contacts the fixed electrode plate. Further, the outside case which covers the electromagnet and other inside parts is formed into a rectangular parallelepiped shape. In this case, the moving electrode plate and fixed electrode plate are arranged so that their width directions become vertical or parallel to the outside surfaces of the case. When the moving electrode plate deforms, a switching operation is performed while maintaining a state where the width direction of the moving electrode plate and the width direction of the fixed electrode plate are parallel.
The electromagnetic relay which has such a rectangular parallelepiped shaped case is in many cases arranged on the surface of a board which extends in a horizontal direction or a board which extends in a vertical direction. For this reason, sometimes this is arranged so that the width direction of the moving electrode plate and the width direction of the fixed electrode plate become parallel to the horizontal direction.
In this regard, sometimes the inside of the case of an electromagnetic relay has foreign matter which has an insulating property remaining in it. For example, at the time of assembly of the electromagnetic relay, burrs which formed at the time of plastic molding drop down as foreign matter or dust etc. in the air invades the inside of the case as foreign matter. Further, sometimes electrode plates or other parts are press fit at a base member which is formed by resin etc. in the manufacturing process. In this case, sometimes the base member is scraped and forms foreign matter.
If such insulating foreign matter remains inside of the case and deposits on a moving contact of the moving electrode plate and a fixed contact of the fixed electrode plate, poor conduction will result when making the moving contact and the fixed contact contact each other. The moving contact of the moving electrode plate moves and contacts the fixed contact, so sometimes foreign matter which had deposited on the contacts drops off along with the operation. In this regard, as explained above, when the parts are arranged so that the width direction of the moving electrode plate and the width direction of the fixed electrode plate become parallel with the horizontal direction, sometimes foreign matter ends up being carried on the surfaces of the electrode plates and even if the moving electrode plate operates, the foreign matter remains without dropping off. For this reason, sometimes poor conduction occurs between the moving electrode plate and the fixed electrode plate.